Carbon dioxide energy storage system

Abstract

The utility model provides a carbon dioxide energy storage system, relates to the technical field of energy storage, and aims to solve the problem of low energy storage efficiency of the carbon dioxide energy storage system. The carbon dioxide energy storage system comprises a first storage subsystem, a second storage subsystem, a first valve, a second valve, a charging subsystem used for compressing carbon dioxide and a discharging subsystem enabling the carbon dioxide to expand to do work. The first storage subsystem comprises a first storage device and a first balancing weight, the second storage subsystem comprises a second storage device and a second balancing weight, and the pressure intensity of carbon dioxide in a third cavity of the second storage device is larger than that of carbon dioxide in a first cavity of the first storage device. The first balancing weight slides under the action of the gravity of the first balancing weight; and under the condition that the carbon dioxide in the third cavity flows out, the second balancing weight slides under the action of the gravity of the second balancing weight. The energy storage efficiency of the carbon dioxide energy storage system can be improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a carbon dioxide energy storage system. Background Art

[0002] Carbon dioxide can be stored in gaseous, liquid or supercritical form. Conventional compressed carbon dioxide energy storage systems usually use fixed-volume tanks to store high-pressure carbon dioxide, and use air bags or fixed-volume tanks to store low-pressure carbon dioxide. When using fixed-volume tanks for storage, during the storage and release process, as the carbon dioxide flows into or out of the high / low storage container, the tank pressure may fluctuate. Usually, a circulating pump or a throttle valve is used to maintain the compressor and expander inlet pressure stable. However, the use of a circulating pump will increase additional power consumption, and the use of a throttle valve will cause the loss of internal energy of the carbon dioxide, resulting in a low energy storage efficiency of the compressed carbon dioxide energy storage system. Utility Model Content

[0003] The embodiment of the present application provides a carbon dioxide energy storage system to solve the problem of low energy storage efficiency of the carbon dioxide energy storage system.

[0004] To solve the above technical problems, this application is implemented as follows:

[0005] The embodiment of the present application provides a carbon dioxide energy storage system, comprising: a first storage subsystem, a second storage subsystem, a first valve, a second valve, a charging subsystem for compressing carbon dioxide, and a discharging subsystem for expanding carbon dioxide to do work;

[0006] The first storage subsystem includes a first storage device, a first counterweight block and a first pipeline. The first counterweight block is accommodated in the first storage device. The first counterweight block is in contact with the inner wall of the first storage device to separate the first storage device into a first cavity and a second cavity. The first counterweight block is slidably connected to the first storage device. The first cavity is used to store carbon dioxide. The first cavity is connected to the first valve through the first pipeline, and the first valve is connected to the input end of the charging subsystem. The output end of the charging subsystem is connected to the second storage subsystem through the second valve.

[0007] The second storage subsystem includes a second storage device, a second counterweight block and a second pipeline, the second counterweight block is accommodated in the second storage device, the second counterweight block is in contact with the inner wall of the second storage device to separate the second storage device into a third cavity and a fourth cavity, the second counterweight block is slidably connected to the second storage device, the third cavity is used to store carbon dioxide, the third cavity is connected to the second valve through the second pipeline, and the second valve is connected to the input end of the discharge subsystem, and the output end of the discharge subsystem is connected to the first storage subsystem through the first valve;

[0008] The pressure of the carbon dioxide in the third cavity is greater than the pressure of the carbon dioxide in the first cavity. When the carbon dioxide in the first cavity flows out, the first counterweight slides toward one side of the first cavity under the action of its own gravity; when the carbon dioxide in the third cavity flows out, the second counterweight slides toward one side of the third cavity under the action of its own gravity;

[0009] Wherein, when the carbon dioxide energy storage system is in a charging state, the first valve connects the first cavity with the input end of the charging subsystem, and the second valve connects the output end of the charging subsystem with the third cavity;

[0010] When the carbon dioxide energy storage system is in a discharging state, the second valve connects the third cavity with the input end of the discharge subsystem, and the first valve connects the output end of the discharge subsystem with the first cavity.

[0011] In the embodiment of the present application, the above-mentioned carbon dioxide energy storage system can use the first cavity formed by the first counterweight block and the first storage device and the third cavity formed by the second counterweight block and the second storage device to store carbon dioxide. When the carbon dioxide energy storage system is in a charging state, the first valve connects the first cavity with the input end of the charging subsystem, and the second valve connects the output end of the charging subsystem with the third cavity. Carbon dioxide flows out of the first cavity, is compressed by the charging subsystem and flows into the third cavity. The first counterweight block slides toward one side of the first cavity under the action of its own gravity, and the second counterweight block slides toward one side of the fourth cavity under the push of carbon dioxide. When the carbon dioxide energy storage system is in a discharging state, the second valve connects the third cavity with the input end of the discharge subsystem, and the first valve connects The output end of the discharge subsystem is connected to the first cavity, and carbon dioxide flows out of the third cavity, and flows into the first cavity after the discharge subsystem expands and does work. The second counterweight slides toward the third cavity under the action of its own gravity, and the first counterweight slides toward the second cavity under the push of carbon dioxide, that is, the first counterweight and the second counterweight will slide with the volume change of carbon dioxide in the first cavity and the third cavity, so that the storage pressure of carbon dioxide in the first cavity and the third cavity can be maintained stable, and the pressure at the input end of the charging subsystem and the discharge subsystem can be maintained stable without using a circulating pump or a throttle valve, which can simplify the system structure, thereby reducing the energy consumption of the carbon dioxide energy storage system, and reducing the internal energy loss of carbon dioxide, thereby improving the energy storage efficiency of the carbon dioxide energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0013] Figure 1 One of the schematic diagrams of a carbon dioxide energy storage system provided in an embodiment of the present application;

[0014] Figure 2 A schematic diagram of a three-way valve provided in an embodiment of the present application;

[0015] Figure 3 A second schematic diagram of a carbon dioxide energy storage system provided in an embodiment of the present application;

[0016] Figure 4A third schematic diagram of a carbon dioxide energy storage system provided in an embodiment of the present application;

[0017] Figure 5 This is a fourth schematic diagram of a carbon dioxide energy storage system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0019] Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0020] See also Figure 1 , Figure 1 is one of the structural schematic diagrams of a carbon dioxide energy storage system provided in an embodiment of the present application, such as Figure 1 As shown, the carbon dioxide energy storage system includes: a first storage subsystem, a second storage subsystem, a first valve 300, a second valve 400, a charging subsystem for compressing carbon dioxide, and a discharging subsystem for expanding carbon dioxide to do work;

[0021] The first storage subsystem includes a first storage 110, a first counterweight 120 and a first pipeline 130. The first counterweight 120 is accommodated in the first storage 110. The first counterweight 120 is in contact with the inner wall of the first storage 110 to separate the first storage 110 into a first cavity 111 and a second cavity 112. The first counterweight 120 is slidably connected to the first storage 110. The first cavity 111 is used to store carbon dioxide. The first cavity 111 is connected to the first valve 300 through the first pipeline 130, and the first valve 300 is connected to the input end of the charging subsystem. The output end of the charging subsystem is connected to the second storage subsystem through the second valve 400.

[0022] The second storage subsystem includes a second storage 210, a second counterweight 220 and a second pipeline 230. The second counterweight 220 is accommodated in the second storage 210. The second counterweight 220 is in contact with the inner wall of the second storage 210 to separate the second storage 210 into a third cavity 211 and a fourth cavity 212. The second counterweight 220 is slidably connected to the second storage 210. The third cavity 211 is used to store carbon dioxide. The third cavity 211 is connected to the second valve 400 through the second pipeline 230, and the second valve 400 is connected to the input end of the discharge subsystem. The output end of the discharge subsystem is connected to the first storage subsystem through the first valve 300.

[0023] The pressure of the carbon dioxide in the third cavity 211 is greater than the pressure of the carbon dioxide in the first cavity 111. When the carbon dioxide in the first cavity 111 flows out, the first counterweight 120 slides toward the first cavity 111 under the action of its own gravity. When the carbon dioxide in the third cavity 211 flows out, the second counterweight 220 slides toward the third cavity 211 under the action of its own gravity.

[0024] Wherein, when the carbon dioxide energy storage system is in a charging state, the first valve 300 connects the first cavity 111 with the input end of the charging subsystem, and the second valve 400 connects the output end of the charging subsystem with the third cavity 211;

[0025] When the carbon dioxide energy storage system is in a discharging state, the second valve 400 connects the third chamber 211 with the input end of the discharge subsystem, and the first valve 300 connects the output end of the discharge subsystem with the first chamber 111 .

[0026] Specifically, the first storage subsystem and the second storage subsystem may be subsystems respectively used to store carbon dioxide at different pressures, and the storage pressure of carbon dioxide in the second storage subsystem is greater than the storage pressure of carbon dioxide in the first storage subsystem, wherein the carbon dioxide in the first storage subsystem may be stored in a gaseous or supercritical form, and the carbon dioxide in the second storage subsystem may also be stored in a gaseous or supercritical form.

[0027] The first valve 300 and the second valve 400 may be three-way valves, for example, Figure 2 A schematic diagram of a three-way valve provided in an embodiment of the present application, such as Figure 2As shown, the three-way valve includes three passages, A is the first passage, B is the second passage, and C is the third passage. The flow direction of the working medium in the three-way valve can be changed by opening any two of the three passages and closing the third passage.

[0028] The charging subsystem can be used to compress carbon dioxide, which can be understood as the charging subsystem using electrical energy to compress carbon dioxide, that is, converting electrical energy into the internal energy of carbon dioxide for storage, so as to realize the charging process of the carbon dioxide energy storage system. The discharging subsystem can be used to expand carbon dioxide to do work, which can be understood as the discharging subsystem using the expansion work of carbon dioxide to generate electricity, that is, converting the internal energy of carbon dioxide into electrical energy, so as to realize the discharging process of the carbon dioxide energy storage system.

[0029] The first storage device 110 and the second storage device 210 may be containers for storing carbon dioxide, and both need to ensure good sealing. For example, abandoned mines or artificially excavated shafts may be used, which are reinforced and sealed, and are used in conjunction with piston-type weight blocks to form a carbon dioxide working medium storage volume without the need to build huge storage containers on the ground. This can reduce the floor area and save ground space. Storage tanks or other containers may also be used, and the present application does not make specific limitations on this.

[0030] The first counterweight block 120 fits tightly against the inner wall of the first storage 110, and a sealing device may be provided between the side of the first counterweight block 120 and the inner wall of the first storage 110, and between the side of the second counterweight block 220 and the inner wall of the second storage 210, so as to ensure that the first storage subsystem and the second storage subsystem have good sealing properties.

[0031] It should be noted that, since the carbon dioxide working fluid is corrosive to a certain extent, the outer walls of the first counterweight block 120 and the second counterweight block 220 may be coated with an anti-corrosion coating.

[0032] The above-mentioned first pipeline 130 can be used to connect the first cavity 111 of the first storage 110 and the first valve 300. The above-mentioned first counterweight block 120 separates the first storage 110 into a first cavity 111 and a second cavity 112. It can be understood that when the above-mentioned first counterweight block 120 slides toward the side of the first cavity 111, the volume of the first cavity 111 decreases and the volume of the second cavity 112 increases; when the above-mentioned first counterweight block 120 slides toward the side of the second cavity 112, the volume of the second cavity 112 decreases and the volume of the first cavity 111 increases.

[0033] The above-mentioned second pipeline 230 can be used to connect the third cavity 211 of the second storage device 210 and the second valve 400. The above-mentioned second counterweight block 220 separates the second storage device 210 into a third cavity 211 and a fourth cavity 212. It can be understood that when the above-mentioned second counterweight block 220 slides toward the side of the third cavity 211, the volume of the third cavity 211 decreases and the volume of the fourth cavity 212 increases; when the above-mentioned second counterweight block 220 slides toward the side of the fourth cavity 212, the volume of the fourth cavity 212 decreases and the volume of the third cavity 211 increases.

[0034] It can be understood that, when the carbon dioxide energy storage system is in a charging state, the first valve 300 conducts between the first cavity 111 and the input end of the charging subsystem, and the second valve 400 conducts between the output end of the charging subsystem and the third cavity 211. At the same time, the first valve 300 disconnects the flow path between the output end of the discharge subsystem and the first cavity 111, and the second valve 400 disconnects the flow path between the input end of the discharge subsystem and the third cavity 211. For example, Figure 1 As shown, when the carbon dioxide energy storage system is in a charging state, the first valve 300 connects the first passage and the second passage of the first valve 300 and closes the third passage, and the second valve 400 connects the first passage and the second passage of the second valve 400 and closes the third passage.

[0035] It can be understood that, when the carbon dioxide energy storage system is in the discharge state, the second valve 400 conducts the third cavity 211 and the input end of the discharge subsystem, and the first valve 300 conducts the output end of the discharge subsystem and the first cavity 111. At the same time, the first valve 300 disconnects the flow path between the first cavity 111 and the input end of the charging subsystem, and the second valve 400 disconnects the flow path between the output end of the charging subsystem and the third cavity 211. For example, Figure 1 As shown, when the carbon dioxide energy storage system is in a discharging state, the first valve 300 connects the first passage and the third passage of the first valve 300 and closes the second passage, and the second valve 400 connects the second passage and the third passage of the second valve 400 and closes the first passage.

[0036] In the embodiment of the present application, the above-mentioned carbon dioxide energy storage system can use the first cavity 111 formed by the first counterweight block 120 and the first storage device 110 and the third cavity 211 formed by the second counterweight block 220 and the second storage device 210 to store carbon dioxide. When the carbon dioxide energy storage system is in a charging state, the first valve 300 connects the first cavity 111 with the input end of the charging subsystem, and the second valve 400 connects the output end of the charging subsystem with the third cavity 211. Carbon dioxide flows out of the first cavity 111, is compressed by the charging subsystem, and flows into the third cavity 211. The first counterweight block 120 slides toward one side of the first cavity 111 under the action of its own gravity, and the second counterweight block 220 slides toward one side of the fourth cavity 212 under the push of carbon dioxide. When the carbon dioxide energy storage system is in a discharging state, the second valve 400 connects the third cavity 211 with the input end of the discharge subsystem. The first valve 300 connects the output end of the discharge subsystem with the first cavity 111, and the carbon dioxide flows out of the third cavity 211, and flows into the first cavity 111 after the discharge subsystem expands and does work. The second counterweight 220 slides toward the third cavity 211 under the action of its own gravity, and the first counterweight 120 slides toward the second cavity 112 under the push of the carbon dioxide, that is, the first counterweight 120 and the second counterweight 220 will slide with the volume change of the carbon dioxide in the first cavity 111 and the third cavity 211, so that the storage pressure of the carbon dioxide in the first cavity 111 and the third cavity 211 can be maintained stable, and the pressure at the input end of the charging subsystem and the discharge subsystem can be maintained stable without using a circulating pump or a throttle valve, which can simplify the system structure, thereby reducing the energy consumption of the carbon dioxide energy storage system, and reducing the internal energy loss of carbon dioxide, thereby improving the energy storage efficiency of the carbon dioxide energy storage system.

[0037] Optionally, when the carbon dioxide energy storage system is in a charging state, the carbon dioxide in the first cavity 111 flows into the third cavity 211 through the charging subsystem, and the first counterweight 120 slides toward the first cavity 111 under the action of its own gravity, so that the volume of the first cavity 111 is reduced, and the second counterweight 220 slides toward the fourth cavity 212 under the push of the carbon dioxide in the third cavity 211, so that the volume of the third cavity 211 is increased;

[0038] When the carbon dioxide energy storage system is in a discharging state, the carbon dioxide in the third cavity 211 flows into the first cavity 111 through the discharge subsystem, and the second counterweight 220 slides toward the third cavity 211 under the action of its own gravity to reduce the volume of the third cavity 211. The first counterweight 120 slides toward the second cavity 112 under the push of the carbon dioxide in the first cavity 111 to increase the volume of the first cavity 111.

[0039] Specifically, when the carbon dioxide energy storage system is in a charging state, the carbon dioxide in the first cavity 111 flows into the charging subsystem through the first valve 300, and the charging subsystem compresses the inflowing carbon dioxide, and the compressed carbon dioxide flows into the third cavity 211 through the second valve 400. As the carbon dioxide in the first cavity 111 flows out, the volume of the carbon dioxide in the first cavity 111 decreases, and the first counterweight 120 slides toward the first cavity 111 under the action of its own gravity, so that the volume of the first cavity 111 decreases. As the carbon dioxide flows into the third cavity 211, the second counterweight 220 slides toward the fourth cavity 212 under the push of the carbon dioxide, so that the volume of the third cavity 211 increases.

[0040] When the carbon dioxide energy storage system is in a discharging state, the carbon dioxide in the third cavity 211 flows into the discharge subsystem through the second valve 400, and the inflowing carbon dioxide expands and does work in the discharge subsystem. The carbon dioxide after expansion and work flows into the first cavity 111 through the first valve 300. As the carbon dioxide in the third cavity 211 flows out, the volume of the carbon dioxide in the third cavity 211 decreases, and the second counterweight block 220 slides toward the third cavity 211 under the action of its own gravity, so that the volume of the third cavity 211 decreases. As the carbon dioxide flows into the first cavity 111, the first counterweight block 120 slides toward the second cavity 112 under the push of the carbon dioxide, so that the volume of the first cavity 111 increases.

[0041] In this embodiment, the first counterweight block 120 and the second counterweight block 220 can slide along the first storage 110 and the second storage 210 according to the change in the carbon dioxide content in the first cavity 111 and the third cavity 211 to change the volume of the first cavity 111 and the third cavity 211, thereby maintaining the pressure in the first cavity 111 and the third cavity 211 stable, thereby improving the stability of carbon dioxide storage in the carbon dioxide energy storage system.

[0042] Optionally, the charging subsystem includes a motor 510 and at least one charging component, the charging component includes a compressor and a charging heat exchanger, the motor 510 is connected to the compressor, the first cavity 111 is connected to the input end of the compressor through the first valve 300, the output end of the compressor is connected to the first input end of the charging heat exchanger, and the first output end of the charging heat exchanger is connected to the third cavity 211 through the second valve 400;

[0043] The discharge subsystem includes a generator 610 and at least one discharge component, and the discharge component includes an expander and a discharge heat exchanger. The generator 610 is connected to the expander, and the third cavity 211 is connected to the first input end of the discharge heat exchanger through the second valve 400, and the first output end of the discharge heat exchanger is connected to the input end of the expander, and the output end of the expander is connected to the first cavity 111 through the first valve 300.

[0044] It should be noted that the charging subsystem may include at least one charging component, each charging component includes a compressor and a charging heat exchanger. For example, the charging subsystem may generally include 2 to 6 charging components, or may include only 1 charging component or more than 6 charging components. When the charging subsystem includes multiple charging components, multiple compressors corresponding to the multiple charging components are coaxially connected; the discharge subsystem may include at least one discharge component, each discharge component includes an expander and a discharge heat exchanger. For example, the charging subsystem may generally include 2 to 6 discharge components, or may include only 1 discharge component or more than 6 discharge components. When the discharge subsystem includes multiple discharge components, multiple expanders corresponding to the multiple discharge components are coaxially connected.

[0045] In this embodiment, the charging subsystem consumes electric energy through the motor 510 to drive the compressor to rotate, converts the electric energy into mechanical energy of the compressor, and then converts the mechanical energy into kinetic energy and internal energy of the carbon dioxide working fluid through the compressor to complete the charging process. The discharging subsystem allows carbon dioxide to enter the expander to expand and perform work, drives the generator 610 to rotate and generate electricity, converts the kinetic energy and internal energy of the carbon dioxide working fluid into mechanical energy of the compressor, and then converts the mechanical energy into electric energy through the generator 610 to complete the discharging process.

[0046] Optionally, the carbon dioxide energy storage system further includes a heat storage subsystem, a first end of the heat storage subsystem is connected to the second input end of the charging heat exchanger, and a second output end of the charging heat exchanger is connected to the second end of the heat storage subsystem;

[0047] The second end of the heat storage subsystem is connected to the second input end of the discharge heat exchanger, and the second output end of the discharge heat exchanger is connected to the first end of the heat storage subsystem.

[0048] Specifically, the heat storage subsystem can be used to exchange heat between the charging subsystem and the discharging subsystem, and specifically can store the heat energy generated by the charging subsystem during the charging process into the heat storage subsystem, and release the stored heat energy to the discharging subsystem during the discharging process.

[0049] Specifically, the first input end and the first output end of the charging heat exchanger form a first transmission channel inside the charging heat exchanger, and the second input end and the second output end of the charging heat exchanger form a second transmission channel inside the charging heat exchanger. It can be understood that when the carbon dioxide energy storage system is in a charging state, the heat transfer medium in the thermal storage subsystem flows from the first end of the thermal storage subsystem into the second transmission channel to exchange heat with the carbon dioxide in the first transmission channel. The temperature of the heat transfer medium flowing into the second transmission channel is lower than the temperature of the carbon dioxide in the first transmission channel. The heat transfer medium flowing into the second transmission channel absorbs the thermal energy of the carbon dioxide and then flows into the second end of the thermal storage subsystem to store the thermal energy in the thermal storage subsystem.

[0050] Specifically, the first input end and the first output end of the discharge heat exchanger form a third transmission channel inside the discharge heat exchanger, and the second input end and the second output end of the discharge heat exchanger form a fourth transmission channel inside the discharge heat exchanger. It can be understood that when the carbon dioxide energy storage system is in a discharging state, the heat transfer medium in the thermal storage subsystem flows from the second end of the thermal storage subsystem into the fourth transmission channel to exchange heat with the carbon dioxide in the third transmission channel. The temperature of the heat transfer medium flowing into the fourth transmission channel is greater than the temperature of the carbon dioxide in the third transmission channel. The heat transfer medium flowing into the fourth transmission channel releases heat energy and then flows into the first end of the thermal storage subsystem.

[0051] In this embodiment, the carbon dioxide energy storage power supply system further includes a heat storage subsystem, a first end of the heat storage subsystem is connected to the second input end of the charging heat exchanger, a second output end of the charging heat exchanger is connected to the second end of the heat storage subsystem, a second end of the heat storage subsystem is connected to the second input end of the discharging heat exchanger, and a second output end of the discharging heat exchanger is connected to the first end of the heat storage subsystem, so that the heat energy generated by the charging subsystem during the charging process can be stored in the heat storage subsystem, and the heat energy stored in the heat storage subsystem can be released to the discharging subsystem during the discharging process, thereby improving the utilization rate of energy, thereby further improving the energy storage efficiency of the carbon dioxide energy storage system.

[0052] Optionally, the heat storage subsystem includes a heat storage device 710, a circulation device 720, at least one third valve and at least one fourth valve, the at least one charging component and the at least one discharging component correspond to the at least one third valve respectively, and the at least one charging component and the at least one discharging component correspond to the at least one fourth valve respectively;

[0053] The first end of the heat accumulator 710 is connected to the first end of the circulation device 720, the second end of the circulation device 720 is connected to the second input end of the corresponding charging heat exchanger through the third valve, and the second end of the heat accumulator 710 is connected to the second output end of the corresponding charging heat exchanger through the fourth valve;

[0054] The second end of the heat accumulator 710 is connected to the second input end of the corresponding discharge heat exchanger through the fourth valve, and the second end of the circulation device 720 is connected to the second output end of the corresponding discharge heat exchanger through the third valve.

[0055] Specifically, the solid filler in the above-mentioned heat accumulator 710 can be spherical or irregularly shaped metal particles, rock particles, or microcapsules of phase change materials that meet the working temperature range, for example, phase change materials include but are not limited to paraffin, alcohols, lipids, fatty acids, hydrated salts, alloys, hydroxides, etc. The heat transfer medium in the heat storage subsystem can be gases such as air, nitrogen, argon, helium, as well as liquid working fluids such as heat transfer oil and water that match the heat storage temperature of the compressed carbon dioxide system. This application does not make specific limitations on this.

[0056] The circulation device 720 may be a device for controlling the circulation flow of the heat transfer medium, and may specifically match the form of the heat transfer medium. For example, when the heat transfer medium is a gas, the circulation device 720 may be a circulation fan, and when the heat transfer medium is a liquid, the circulation device 720 may be a circulation pump. The third valve and the fourth valve may be three-way valves.

[0057] Specifically, the second end of the above-mentioned circulation device 720 is connected to the second input end of the corresponding charging heat exchanger through the third valve, wherein the corresponding charging heat exchanger can be understood as the charging heat exchanger in the charging component corresponding to the third valve; the second end of the above-mentioned heat accumulator 710 is connected to the second output end of the corresponding charging heat exchanger through the fourth valve, wherein the corresponding charging heat exchanger can be understood as the charging heat exchanger in the charging component corresponding to the fourth valve; the second end of the above-mentioned heat accumulator 710 is connected to the second input end of the corresponding discharge heat exchanger through the fourth valve, wherein the corresponding discharge heat exchanger can be understood as the discharge heat exchanger in the discharge component corresponding to the fourth valve; the second end of the circulation device 720 is connected to the second output end of the corresponding discharge heat exchanger through the third valve, wherein the corresponding discharge heat exchanger can be understood as the discharge heat exchanger in the discharge component corresponding to the third valve.

[0058] In this embodiment, the heat storage subsystem includes a heat accumulator 710, a circulation device 720, at least one third valve and at least one fourth valve. During the charging process, the circulation device 720 controls the heat transfer medium of the heat storage subsystem to flow into the charging subsystem to cool the carbon dioxide in the charging subsystem. After absorbing heat energy, the heat transfer medium flows into the heat accumulator 710 to exchange heat with the filler in the heat accumulator 710, and stores the heat energy in the heat accumulator 710. During the discharging process, the circulation device 720 controls the heat transfer medium of the heat storage subsystem to flow into the heat accumulator 710 to exchange heat with the filler in the heat accumulator 710. After absorbing heat energy, the heat transfer medium flows into the discharge subsystem to heat the carbon dioxide in the discharge subsystem, thereby improving the energy utilization rate, thereby further improving the energy storage efficiency of the carbon dioxide energy storage system.

[0059] Alternatively, if Figure 1 As shown, the at least one third valve includes a fifth valve 731 and a sixth valve 732, the at least one fourth valve includes a seventh valve 741 and an eighth valve 742, the at least one charging component includes a first compressor 521, a first charging heat exchanger 522, a second compressor 523, and a second charging heat exchanger 524, and the at least one discharging component includes a first expander 621, a first discharging heat exchanger 622, a second expander 623, and a second discharging heat exchanger 624;

[0060] The first compressor 521 and the second compressor 523 are connected to the motor 510 respectively, the first cavity 111 is connected to the input end of the first compressor 521 through the first valve 300, the output end of the first compressor 521 is connected to the first input end of the first charging heat exchanger 522, the first output end of the first charging heat exchanger 522 is connected to the input end of the second compressor 523, the output end of the second compressor 523 is connected to the first input end of the second charging heat exchanger 524, and the first output end of the second charging heat exchanger 524 is connected to the third cavity 211 through the second valve 400;

[0061] The second end of the circulation device 720 is connected to the second input end of the first charging heat exchanger 522 through the fifth valve 731, the second output end of the first charging heat exchanger 522 is connected to the second end of the heat accumulator 710 through the seventh valve 741, the second end of the circulation device 720 is connected to the second input end of the second charging heat exchanger 524 through the sixth valve 732, and the second output end of the second charging heat exchanger 524 is connected to the second end of the heat accumulator 710 through the eighth valve 742;

[0062] The first expander 621 and the second expander 623 are connected to the generator 610 respectively, the third cavity 211 is connected to the first input end of the first discharge heat exchanger 622 through the second valve 400, the first output end of the first discharge heat exchanger 622 is connected to the input end of the first expander 621, the output end of the first expander 621 is connected to the first input end of the second discharge heat exchanger 624, the first output end of the second discharge heat exchanger 624 is connected to the input end of the second expander 623, and the output end of the second expander 623 is connected to the first cavity 111 through the first valve 300;

[0063] The second end of the heat accumulator 710 is connected to the second input end of the first discharge heat exchanger 622 through the eighth valve 742, the second output end of the first discharge heat exchanger 622 is connected to the second end of the circulation device 720 through the sixth valve 732, the second end of the heat accumulator 710 is connected to the second input end of the second discharge heat exchanger 624 through the seventh valve 741, and the second output end of the second discharge heat exchanger 624 is connected to the second end of the circulation device 720 through the fifth valve 731.

[0064] It can be understood that the fifth valve 731 and the sixth valve 732 are the third valves. For the convenience of distinction, the two third valves are named the fifth valve 731 and the sixth valve 732. The seventh valve 741 and the eighth valve 742 are the fourth valves. For the convenience of distinction, the two fourth valves are named the seventh valve 741 and the eighth valve 742.

[0065] Specifically, when the carbon dioxide energy storage system is in a charging state, the carbon dioxide working fluid flows through the first compressor 521 for compression, the first charging heat exchanger 522, the second compressor 523, and the second charging heat exchanger 524, and undergoes the processes of compression temperature increase and pressure increase, heat exchange and temperature reduction, compression temperature increase and pressure increase, and heat exchange and temperature reduction to a normal temperature and high pressure state; the first compressor 521 and the second compressor 523 are coaxially connected, and the motor 510 consumes electric energy to drive the first compressor 521 and the second compressor 523 to rotate, converting the electric energy into mechanical energy of the compressor, and then converting the mechanical energy into kinetic energy and internal energy of the carbon dioxide working fluid through the compressor; at the same time, The first and second passages of the seventh valve 741 and the eighth valve 742 are connected, and the third passage is closed; the first and third passages of the fifth valve 731 are connected, and the second passage is closed; the second and third passages of the sixth valve 732 are connected, and the first passage is closed; the circulation device 720 is started to drive the heat transfer medium of the heat storage subsystem to flow into the first charging heat exchanger 522 and the second charging heat exchanger 524 through the fifth valve 731 and the sixth valve 732 to exchange heat with the carbon dioxide working medium, and after absorbing heat energy, it flows into the heat accumulator 710 through the seventh valve 741 and the eighth valve 742 to exchange heat with the filler in the heat accumulator 710, and the heat energy is stored in the heat accumulator 710.

[0066] Specifically, when the carbon dioxide energy storage system is in a discharging state, the gaseous or supercritical carbon dioxide working medium flows into the first discharge heat exchanger 622 to absorb heat energy, then enters the first expander 621 to expand and do work, then enters the second discharge heat exchanger 624 to absorb heat again, and then enters the second expander 623 to expand and do work. The first expander 621 and the second expander 623 are coaxially connected to drive the generator 610 to rotate and generate electricity; at the same time, the second and third passages of the seventh valve 741 are connected, and the first passage is closed; the first and third passages of the eighth valve 742 are connected, and the second passage is closed; the first and second passages of the fifth valve 731 and the sixth valve 732 are connected, and the third passage is closed; the circulation device 720 is started to rotate in the opposite direction, driving the heat transfer working medium to flow in from the bottom of the heat accumulator 710, exchange heat with the solid filler in the heat accumulator 710, absorb heat energy, and then flow out from the top of the heat accumulator 710, pass through the seventh valve 741 and the eighth valve 742 respectively, enter the first discharge heat exchanger 622 and the second discharge heat exchanger 624 to release heat energy.

[0067] Alternatively, if Figure 3As shown, the carbon dioxide energy storage system also includes a cold storage device 800, the first cavity 111 is connected to the first input end of the cold storage device 800 through the first valve 300, the first output end of the cold storage device 800 is connected to the input end of the charging subsystem, the output end of the discharge subsystem is connected to the second input end of the cold storage device 800, and the second output end of the cold storage device 800 is connected to the first cavity 111 through the first valve 300.

[0068] Specifically, the solid filler in the above-mentioned cold storage device 800 can be spherical or irregularly shaped metal particles, rock particles, or microcapsules of phase change materials that meet the working temperature range, etc. For example, phase change materials include but are not limited to paraffin, alcohols, lipids, fatty acids, hydrated salts, alloys, hydroxides, etc., and the present application does not make specific limitations on this.

[0069] It can be understood that, since the interior of the cold storage device 800 is filled with a porous medium, the transmission channel formed by the first output end and the first output end of the cold storage device 800 and the transmission channel formed by the second output end and the second output end of the cold storage device 800 are actually the same passage, that is, when the carbon dioxide energy storage system is in a charging state and a discharging state, the flow path of carbon dioxide in the cold storage device 800 is the same, but the flow direction is opposite.

[0070] For example, Figure 3 As shown, when the carbon dioxide energy storage system is in a charging state, the carbon dioxide in the first cavity 111 enters the cold storage device 800 through the first valve 300, exchanges heat with the filler in the cold storage device 800, and stores the cold energy of the carbon dioxide therein. When the carbon dioxide in the first cavity 111 is liquid, the temperature of the liquid carbon dioxide rises and vaporizes to a normal temperature and low-pressure gas state. When the carbon dioxide energy storage system is in a discharging state, the carbon dioxide output by the discharge subsystem enters the cold storage device 800, absorbs the cold energy stored in the cold storage device 800, and is liquefied. The liquefied carbon dioxide enters the first cavity 111 through the first valve 300.

[0071] In this embodiment, the carbon dioxide energy storage system further includes a cold storage device 800, which can be used to store the cold energy of the carbon dioxide flowing out of the first cavity 111 in the cold storage device 800, and realize the gasification of liquid carbon dioxide, so that the charging subsystem can compress the carbon dioxide, and the cold energy stored in the cold storage device 800 can be used to liquefy the gaseous or supercritical carbon dioxide flowing out of the discharge subsystem, thereby improving the energy utilization rate, and allowing the first cavity 111 to store carbon dioxide in liquid form, thereby improving the applicability of the carbon dioxide energy storage system.

[0072] Optionally, the carbon dioxide energy storage system further includes a heat dissipation subsystem, the output end of the charging subsystem is connected to the input end of the heat dissipation subsystem, and the output end of the heat dissipation subsystem is connected to the third cavity 211 through the second valve 400 .

[0073] Specifically, the heat dissipation subsystem may be used to dissipate heat from the carbon dioxide output by the charging subsystem.

[0074] In this embodiment, the carbon dioxide energy storage system further includes a heat dissipation subsystem, and the output end of the charging subsystem is connected to the input end of the heat dissipation subsystem, and the output end of the heat dissipation subsystem is connected to the third cavity 211 through the second valve 400, so that the gaseous or supercritical carbon dioxide output by the charging subsystem can enter the heat dissipation subsystem for heat dissipation, so as to dissipate waste heat, reduce the temperature and convert it into liquid carbon dioxide, so that the third cavity 211 can store carbon dioxide in liquid form, thereby improving the applicability of the carbon dioxide energy storage system.

[0075] Alternatively, if Figure 4 As shown, the heat dissipation subsystem includes a radiator 910, a circulating water pump 920, and a cooling water tank 930;

[0076] The output end of the charging subsystem is connected to the first input end of the radiator 910, the first output end of the radiator 910 is connected to the third cavity 211 through the second valve 400, the output end of the cooling water tank 930 is connected to the input end of the circulating water pump 920, the output end of the circulating water pump 920 is connected to the second input end of the radiator 910, and the second output end of the radiator 910 is connected to the input end of the cooling water tank 930.

[0077] Specifically, the circulating water pump 920 may be a device for controlling the circulation of liquid in the cooling water tank 930, and the cooling water tank 930 may be a container device for storing cooling water. The first input end and the first output end of the radiator 910 form a fifth transmission channel inside the radiator 910, and the second input end and the second output end of the radiator 910 form a sixth transmission channel inside the radiator 910.

[0078] For example, Figure 4 As shown, when the carbon dioxide energy storage system is in a charging state, the carbon dioxide working medium flowing out of the charging subsystem flows into the fifth transmission channel, and at the same time the circulating water pump 920 is started to drive the cooling water working medium to flow out of the cooling water tank 930, enter the sixth transmission channel, absorb the waste heat of the carbon dioxide in the fifth transmission channel, and then return to the cooling water tank 930.

[0079] It should be noted that, when both the first cavity 111 and the second cavity 112 store carbon dioxide in liquid form, the carbon dioxide energy storage power supply system may include both the cold storage device 800 and the heat dissipation subsystem. For example, Figure 5 As shown, the carbon dioxide energy storage power supply system includes a cold storage device 800 and a heat dissipation subsystem. It should be noted that when the carbon dioxide in the first cavity 111 is stored in a liquid or supercritical state, the first storage device 110 needs to be well insulated; when the carbon dioxide in the second cavity 112 is stored in a gaseous state, a supercritical state or a liquid state, the second storage device 210 needs to be well insulated.

[0080] In this embodiment, the heat dissipation subsystem includes a radiator 910, a circulating water pump 920, and a cooling water tank 930. The circulating water pump 920 is used to drive the cooling water medium to flow from the cooling water tank 930 into the radiator 910, and the carbon dioxide in the radiator 910 is heat-dissipated, and the carbon dioxide output by the charging subsystem is converted into a liquid form, so that the third cavity 211 can store carbon dioxide in a liquid form, thereby further improving the applicability of the carbon dioxide energy storage system.

[0081] Optionally, the mass of the first counterweight 120 is smaller than the mass of the second counterweight 220, the product of the density of the first counterweight 120 and the first length is smaller than the product of the density of the second counterweight 220 and the second length, the first counterweight 120 slides along the length direction of the first storage 110, and the second counterweight 220 slides along the length direction of the second storage 210, the first length is the dimension of the first counterweight 120 along the length direction of the first storage 110, and the second length is the dimension of the second counterweight 220 along the length direction of the second storage 210.

[0082] Specifically, the relationship between the storage pressure (Pa) of carbon dioxide in the first cavity 111 and the second cavity 112 and the mass (kg) of the first counterweight block 120 and the second counterweight block 220 is as shown in the following formula:

[0083] P1=m1g / S1

[0084] P2=m2g / S2

[0085] Among them, P1 is the pressure of the first counterweight block 120 on the carbon dioxide working medium in the first cavity 111, that is, the storage pressure of carbon dioxide in the first cavity 111, m1 is the mass of the first counterweight block 120, S1 is the cross-sectional area of ​​the first counterweight block 120 toward the first cavity 111, P2 is the pressure of the second counterweight block 220 on the carbon dioxide working medium in the second cavity 112, that is, the storage pressure of carbon dioxide in the second cavity 112, m2 is the mass of the second counterweight block 220, S2 is the cross-sectional area of ​​the second counterweight block 220 toward the second cavity 112, and g is the gravitational acceleration.

[0086] The above formula can be converted into the density (kg / m 3 ), thickness of the counterweight (m), acceleration of gravity (m / s 2 ) and the carbon dioxide storage pressure (Pa):

[0087] P1=ρ1gL1

[0088] P2=ρ2gL2

[0089] Among them, ρ1 is the density of the first counterweight block 120, ρ2 is the density of the second counterweight block 220, L1 is the thickness of the first counterweight block 120, that is, the dimension of the first counterweight block 120 along the length direction of the first storage device 110, and L2 is the thickness of the second counterweight block 220, that is, the dimension of the second counterweight block 220 along the length direction of the second storage device 210.

[0090] In this embodiment, the product of the density and the first length of the first counterweight 120 is smaller than the product of the density and the second length of the second counterweight 220. The first counterweight 120 slides along the length direction of the first storage device 110, and the second counterweight 220 slides along the length direction of the second storage device 210. The first length is the dimension of the first counterweight 120 along the length direction of the first storage device 110, and the second length is the dimension of the second counterweight 220 along the length direction of the second storage device 210. As a result, the pressure of the carbon dioxide working medium in the first cavity 111 exerted by the first counterweight 120 is smaller than the pressure of the carbon dioxide working medium in the second cavity 112 exerted by the second counterweight 220.

[0091] It can be understood that when the carbon dioxide energy storage system is in a charging state, low-pressure carbon dioxide working fluid flows out of the first cavity 111, and the first counterweight block 120 falls; high-pressure carbon dioxide working fluid flows into the third cavity 211, and the second counterweight block 220 gradually rises; the mass of the second counterweight block 220 is greater than the mass of the first counterweight block 120, and a part of the electrical energy is converted into the gravitational potential energy of the weight block and stored.

[0092] When the carbon dioxide energy storage system is in a discharging state, high-pressure carbon dioxide flows out from the third cavity 211, and the second counterweight 220 falls; low-pressure carbon dioxide flows into the first cavity 111, and the first counterweight 120 gradually rises; the mass of the second counterweight 220 is greater than the mass of the first counterweight 120, and there is a gravitational potential energy difference, which is transferred to the carbon dioxide working fluid and converted into electrical energy for release through the discharge circuit.

[0093] In this embodiment, since the mass of the second counterweight 220 is greater than that of the first counterweight 120, when the carbon dioxide energy storage system is charged, the first counterweight 120 descends and the second counterweight 220 rises, converting a portion of the extra electrical energy into gravitational potential energy for storage. When the carbon dioxide energy storage system is in a discharging state, the second counterweight 220 descends and the first counterweight 120 rises, and the gravitational potential energy is transferred to the carbon dioxide working fluid, driving the expander to rotate, converting the gravitational potential energy into electrical energy for release through the carbon dioxide system, thereby effectively improving the energy storage scale of the carbon dioxide energy storage system.

[0094] In several embodiments provided in the present application, it should be understood that it should be noted that, in this article, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "include..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0095] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can make several improvements and modifications without departing from the principles described in the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A carbon dioxide energy storage system, characterized in that: include: A first storage subsystem, a second storage subsystem, a first valve, a second valve, a charging subsystem for compressing carbon dioxide, and a discharging subsystem for expanding carbon dioxide to perform work; The first storage subsystem includes a first storage device, a first counterweight block and a first pipeline. The first counterweight block is accommodated in the first storage device. The first counterweight block is in contact with the inner wall of the first storage device to separate the first storage device into a first cavity and a second cavity. The first counterweight block is slidably connected to the first storage device. The first cavity is used to store carbon dioxide. The first cavity is connected to the first valve through the first pipeline, and the first valve is connected to the input end of the charging subsystem. The output end of the charging subsystem is connected to the second storage subsystem through the second valve. The second storage subsystem includes a second storage device, a second counterweight block and a second pipeline, the second counterweight block is accommodated in the second storage device, the second counterweight block is in contact with the inner wall of the second storage device to separate the second storage device into a third cavity and a fourth cavity, the second counterweight block is slidably connected to the second storage device, the third cavity is used to store carbon dioxide, the third cavity is connected to the second valve through the second pipeline, and the second valve is connected to the input end of the discharge subsystem, and the output end of the discharge subsystem is connected to the first storage subsystem through the first valve; The pressure of the carbon dioxide in the third cavity is greater than the pressure of the carbon dioxide in the first cavity. When the carbon dioxide in the first cavity flows out, the first counterweight slides toward one side of the first cavity under the action of its own gravity; when the carbon dioxide in the third cavity flows out, the second counterweight slides toward one side of the third cavity under the action of its own gravity; Wherein, when the carbon dioxide energy storage system is in a charging state, the first valve connects the first cavity with the input end of the charging subsystem, and the second valve connects the output end of the charging subsystem with the third cavity; When the carbon dioxide energy storage system is in a discharging state, the second valve connects the third cavity with the input end of the discharge subsystem, and the first valve connects the output end of the discharge subsystem with the first cavity.

2. The carbon dioxide energy storage system according to claim 1, characterized in that: When the carbon dioxide energy storage system is in a charging state, the carbon dioxide in the first cavity flows into the third cavity through the charging subsystem, and the first counterweight slides toward one side of the first cavity under the action of its own gravity, so that the volume of the first cavity is reduced, and the second counterweight slides toward one side of the fourth cavity under the push of the carbon dioxide in the third cavity, so that the volume of the third cavity is increased; When the carbon dioxide energy storage system is in a discharging state, the carbon dioxide in the third cavity flows into the first cavity through the discharge subsystem, and the second counterweight slides toward one side of the third cavity under the action of its own gravity to reduce the volume of the third cavity. The first counterweight slides toward one side of the second cavity under the push of the carbon dioxide in the first cavity to increase the volume of the first cavity.

3. The carbon dioxide energy storage system according to claim 1, characterized in that: The charging subsystem includes a motor and at least one charging component, the charging component includes a compressor and a charging heat exchanger, the motor is connected to the compressor, the first cavity is connected to the input end of the compressor through the first valve, the output end of the compressor is connected to the first input end of the charging heat exchanger, and the first output end of the charging heat exchanger is connected to the third cavity through the second valve; The discharge subsystem includes a generator and at least one discharge component, the discharge component includes an expander and a discharge heat exchanger, the generator is connected to the expander, the third cavity is connected to the first input end of the discharge heat exchanger through the second valve, the first output end of the discharge heat exchanger is connected to the input end of the expander, and the output end of the expander is connected to the first cavity through the first valve.

4. The carbon dioxide energy storage system according to claim 3, characterized in that: The carbon dioxide energy storage system further includes a heat storage subsystem, a first end of the heat storage subsystem is connected to the second input end of the charging heat exchanger, and a second output end of the charging heat exchanger is connected to the second end of the heat storage subsystem; The second end of the heat storage subsystem is connected to the second input end of the discharge heat exchanger, and the second output end of the discharge heat exchanger is connected to the first end of the heat storage subsystem.

5. The carbon dioxide energy storage system according to claim 4, characterized in that: The thermal storage subsystem comprises a thermal storage device, a circulation device, at least one third valve and at least one fourth valve, the at least one charging component and the at least one discharging component respectively correspond to the at least one third valve, and the at least one charging component and the at least one discharging component respectively correspond to the at least one fourth valve; The first end of the heat accumulator is connected to the first end of the circulation device, the second end of the circulation device is connected to the second input end of the corresponding charging heat exchanger through the third valve, and the second end of the heat accumulator is connected to the second output end of the corresponding charging heat exchanger through the fourth valve; The second end of the heat accumulator is connected to the second input end of the corresponding discharge heat exchanger through the fourth valve, and the second end of the circulation device is connected to the second output end of the corresponding discharge heat exchanger through the third valve.

6. The carbon dioxide energy storage system according to claim 5, characterized in that: The at least one third valve includes a fifth valve and a sixth valve, the at least one fourth valve includes a seventh valve and an eighth valve, the at least one charging assembly includes a first compressor, a first charging heat exchanger, a second compressor, and a second charging heat exchanger, and the at least one discharging assembly includes a first expander, a first discharging heat exchanger, a second expander, and a second discharging heat exchanger; The first compressor and the second compressor are connected to the motor respectively, the first cavity is connected to the input end of the first compressor through the first valve, the output end of the first compressor is connected to the first input end of the first charging heat exchanger, the first output end of the first charging heat exchanger is connected to the input end of the second compressor, the output end of the second compressor is connected to the first input end of the second charging heat exchanger, and the first output end of the second charging heat exchanger is connected to the third cavity through the second valve; The second end of the circulation device is connected to the second input end of the first charging heat exchanger through the fifth valve, the second output end of the first charging heat exchanger is connected to the second end of the heat accumulator through the seventh valve, the second end of the circulation device is connected to the second input end of the second charging heat exchanger through the sixth valve, and the second output end of the second charging heat exchanger is connected to the second end of the heat accumulator through the eighth valve; The first expander and the second expander are connected to the generator respectively, the third cavity is connected to the first input end of the first discharge heat exchanger through the second valve, the first output end of the first discharge heat exchanger is connected to the input end of the first expander, the output end of the first expander is connected to the first input end of the second discharge heat exchanger, the first output end of the second discharge heat exchanger is connected to the input end of the second expander, and the output end of the second expander is connected to the first cavity through the first valve; The second end of the heat accumulator is connected to the second input end of the first discharge heat exchanger through the eighth valve, the second output end of the first discharge heat exchanger is connected to the second end of the circulation device through the sixth valve, the second end of the heat accumulator is connected to the second input end of the second discharge heat exchanger through the seventh valve, and the second output end of the second discharge heat exchanger is connected to the second end of the circulation device through the fifth valve.

7. The carbon dioxide energy storage system according to claim 1, characterized in that: The carbon dioxide energy storage system also includes a cold storage device, the first cavity is connected to a first input end of the cold storage device through the first valve, the first output end of the cold storage device is connected to an input end of the charging subsystem, the output end of the discharge subsystem is connected to a second input end of the cold storage device, and the second output end of the cold storage device is connected to the first cavity through the first valve.

8. The carbon dioxide energy storage system according to any one of claims 1 to 7, characterized in that: The carbon dioxide energy storage system further includes a heat dissipation subsystem, the output end of the charging subsystem is connected to the input end of the heat dissipation subsystem, and the output end of the heat dissipation subsystem is connected to the third cavity through the second valve.

9. The carbon dioxide energy storage system according to claim 8, characterized in that: The heat dissipation subsystem includes a radiator, a circulating water pump, and a cooling water tank; The output end of the charging subsystem is connected to the first input end of the radiator, the first output end of the radiator is connected to the third cavity through the second valve, the output end of the cooling water tank is connected to the input end of the circulating water pump, the output end of the circulating water pump is connected to the second input end of the radiator, and the second output end of the radiator is connected to the input end of the cooling water tank.

10. The carbon dioxide energy storage system according to claim 1, characterized in that: The mass of the first counterweight is smaller than the mass of the second counterweight, the product of the density of the first counterweight and the first length is smaller than the product of the density of the second counterweight and the second length, the first counterweight slides along the length direction of the first storage device, and the second counterweight slides along the length direction of the second storage device, the first length is the dimension of the first counterweight along the length direction of the first storage device, and the second length is the dimension of the second counterweight along the length direction of the second storage device.

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